Process for continuously producing soap and device for carrying out the process

ABSTRACT

A mass of soap ready for forming cakes of soap therefrom is produced in continuous operation by conveying starting materials as conventionally used for the production of soap through a continuous treatment line including a screw extruder with at least two parallel screws, the screw elements of which are in mesh and coact with the inner wall of the casing of the extruder. The screws are divided into sections or groups of screw elements the pitch of which increases in downstream direction. Sections of kneading discs are interposed between selected sections of screw elements to effect kneading and homogenization of the materials. The starting materials are fed into the casing at one end thereof and additives are added through casing openings as the mixture of the starting materials is being conveyed in the casing toward the discharge port thereof. The mixture is discharged from the casing as finished soap of formable consistency. There is also disclosed an installation for carrying out the afore-described method of producing soap in continuous operation.

United States Patent [191 Oclcer Oct. 9, 1973 PROCESS FOR CONTINUOUSLYPRODUCING SOAP AND DEVICE FOR CARRYING OUT THE PROCESS [75] Inventor:HerbertOcker, Leonberg, Germany [73] As signeeWerner8zPfleiderer,Stuttgart- Fleuerbach, Germany 22 Filed: Sept. 7,1971 21 Appl. No.: 178,026

[30] Foreign Application Priority Data Sept. 12, 1970 Germany 20 45272.6

[56] References Cited UNITED STATES PATENTS 4/1963 Street 425/204 2/1967Boden ..l ..259/192 Primary Examiner-Robert W. 'JenkinsAttorneyFrederick E. Hane et al.

[5 7] ABSTRACT A mass of soap ready for forming cakes of soap therefromis produced in continuous operation by conveying starting materials asconventionally used for the production of soap through a continuoustreatment line including a screw extruder with at least two parallelscrews, the screw elements of which are in mesh and coact with the innerwall of the casing of the extruder. The screws are divided into sectionsor groups of screw elements the pitch of which increases in downstreamdirection. Sections of kneading discs are interposed between selectedsections of screw elements to effect kneading and homogenization of thematerials. The starting materials are fed into the casing at one endthereof and additives are added through casing openings as the mixtureof the starting materials is being conveyed in the casing toward thedischarge port thereof. The mixture is discharged from the casing asfinished soap of formable consistency.

There is also disclosed an installation for carrying out theafore-described method of producing soap in continuous operation.

5 Claims, 2 Drawing Figures PATENIEDUET m 3.764.114

HERBERT OCKER PROCESS FOR CONTINUOUSLY PRODUCING SOAP AND DEVICE FORCARRYING OUT THE PROCESS The invention relates to a method of producingsoap in continuous operation and to a device including screw elementsfor carrying out the method.

BACKGROUND In years past and to a certain extent also even at thepresent time the production of soap is effected by means of soapifyingfats with soda lye in boilers. The fatty acids and the lye are thenreacted with the addition of steam and the glycerine formedby thesoapification is washed out with brine. The production of soap by thisprocess requires a considerable period of time just for reaching thesoapification stage and the subsequent process stages that are requiredto perfect the soap necessitate further and very long periods of timeand also complex and expensive installations.

There are known several processes for producing soap which are more orless improved over the aforedescribed initial method, but even theseimproved processes have similar disadvantages. Very frequently they donot produce fully satisfactory high quality soap.

The industry has attempted for many years to develop processes forproducing soap in continuous operation without requiring long periods oftime and costly installations. There is known, for instance, a processfor continually producing soap in which fatty acid as one of thestarting materials is first partly soapified to a selected percentage byreacting fatty acid with soapifying agents such as sodium carbonate,potassium carbonate; etc. Subsequently, the partly soapified fatty acidif fully soapified with soda lye having a suitably selectedconcentration. The soap is now washed in at least two stages with anelectrolyte solution and the electrolyte content in the soap is reducedby washing it with diluted soda lye or potash vlye. The alkali excess isneutralized with fatty acid and the fatty acid content is adjusted for aselected value. If necessary, the percentage of fatty acid may beconcentrated to a selected value.

The starting materials are fed in this process into a two-stagesoapification reactor. An installation for carrying out thejust-described method operates continuously for this purpose; comprisesa continous treatment line which includes, among many other devices,screw elements which act as agitators at selected points of theinstallation and also serve to convey a product through specificselected treatment zones. j I

The described process of continuously producing soap and aninstallationfor carrying out the process are described, for instance, inpublished German Patent Application No. 1,069,319. The disadvantage ofthe described continuously operating process and of the installationtherefor is that the construction costs of the installation are veryhigh and that it requires a very large space, especially if soapis to beproduced in large quantities. Moreover, the time required for carryingout the process is still much higher than desirable.

The same disadvantages are present when the production of soap iscarried to a preliminary stage by one of the known methods, and the thusobtained unfinished product is then kneaded, homogenized and upgraded inseparate screw extruders, as has also been proposed.

THE INVENTION known, is less complex and also less expensive toconstruct and to maintain than comparable installations as heretoforeknown.

SUMMARY OF THE INVENTION The aforepointed out objects, features andadvantages and other objects, features and advantages which will bepointed out hereinafter and are set forth in the appended claimsconstituting part of the invention, are obtained by feeding startingmaterial as suitable and conventional for the manufacture of soap into acontinuous treatment line through which the material is continuously andforcibly conveyed and in which it is subjected continuously to theaction of screw elements rotating crosswise to the length of thetreatment line. As the material passes through the treatment line it isintially subjected to presoapification and is gradually fully soapifiedso that when it leaves the treatment line it constitutes finished soapof pliable and thus formable consistency.

The process of the invention is advantageously carried out in a screwextruder, the casing of which in cludes at its ends a feed port and adischarge port respectively, and if desired also intermediate ports fordegasing the material as it passes through the extruder and for feedingadditivies such as fragrant essences or dyes into the material atselected zones.

The extruder as used for carrying out the process of the inventionincludes at least two screws which are parallel to each other and to theaxis of the casing. The screws are in mesh and also coact with the innerwall of the casing, at least one of the two screws extending through theentire length of the casing. However, it is generally preferable thatboth screws extend through the length, of the casing.

According to one aspect of the invention, the two screws areunidirectionally rotated as tests have shown that the use of two screwsextending through the entire length of the casing and rotated in thesame direction results in minimal installation costs and optimalproduction results.

It has been also found particularly advantageous to provide in the inletzone of the extruder, that is in the zone in which preliminary orpresoapification of the starting material occurs, two meshing screwsections with self-cleaning profiles. This zone including the mesh andself-cleaning screw sections is preferably directly followed indownstream direction by a zone including kneading discs in tightengagement as the provision of a section including kneading discsfacilitates the basic reaction. Moreover, compacting of the mixture ofthe starting materials and further intimate mixing and homogenizingthereof in later stages of the process, can be effected within a shortperiod of time by the provision of one or more sections includingkneading discs.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION In theaccompanying drawing, an installation for carrying out the process ofthe invention is shown by way of illustration and not by way oflimitation.

In the drawing:

FIG. 1 is a diagrammatic lengthwise sectional view of the installation;and

FIG. 2 is a cross-section of FIG. 1 on an enlarged scale.

Referring now to the figures more in detail, only those components ofthe installation are shown that are essential for the understanding ofthe invention.

The installation as exemplified comprises a casing I. This casing may beas is customary and as it is indicated be constructed of severalsections suitably secured to each other but for the purpose of theprocess of the in vention it should be visualized as constituting acontinuous casing. The casing and the devices associated therewith aresupported by a suitable foundation structure indicated at 16. The casingof the extruder includes, as it is conventional, ducts 17 forcirculating a heating system and/or a cooling medium through the casing.Two extruder screws 2 and 2a are rotatably mounted within the casing andunidirectionally driven by conventional drive means indicated at 15.Both screws extend across the length of the casing but in some cases oneof the screws may be shorter than the other. The screw elements are inmesh with each other and the outer peripheral diameters of the screwelements are such that they coact with the inner wall of the casing asit is clearly indicated in FIGS. 1 and 2.

The screw elements of the conveyor screws are subdivided for structuraland also procedural reasons into sections such as, for instance,sections 2b and 26. As it is indicated in FIG. 1, the screw elementshaveidifferently pitched screw turns, either within the sections or withreference to other sections. Sectionalized extruder screws as shown inthe screw extruder of FIG. 1 are well known and conventional in the art;they are constructed by sliding the screw elements on a shaft and keyingthe screw elements thereon. FIG. 2 shows such shafts 4 and screwsections keyed thereon.

FIG. 1 further shows supply containers such as container 5 for asuitable soapifying agent such as soda or potash (potassium carbonate)and container 6 for fatty acids. The materials in containers 5 and 6 arefed via surge tanks 5a and 5b and metering devices 7 of conventionaldesign to a feed port 8 in casing l. The aforereferred to pitchvariations of the screw elements in the different sections of the screwsare selected in accordance with the specific starting materials that areused and also in accordance with the location of the screw elementswithin, as seen in the downstream direction. As it is evident, theprocessing of the starting materials to finished soap occurs insuccessive stages and these stages control and are controlled by theselected configurations of the screw elements. FIG. 1 further showssections of kneading discs 3 interposed between sections of screwelements. The finished product is discharged from the extruder casingthrough a feed port continued by a pipe 14.

The basic reaction of the soapifying process occurs already within thefeed-in zone of the extruder, that is,

the zone at feed port 8. The screw elements will positvely andcontinually carry the materials as they are being converted to soaptoward the discharge end of the casing. The first or feed zone whichincludes sections 2b and 2c, terminates approximately at the location ofthe first section of kneading discs 3 as seen in the downstreamdirection. The screw elements in the feed zone preferably haveself-cleaning tightly meshing profiles. Such screw elements, of course,arewell known in the art and do not constitute part of the invention.

The mixture is subjected to a first compacting action and a particularlyeffective homogenization while passing the first section of kneadingdiscs 3. Just downstream of this section released volatile componentsare discharged through a degasing port 9.

In the feed zone, that is, between port 8 and the first section ofkneading discs 3 additives as conventionally used in the production ofsoap may be added in metered quantities. A conventional metering devicesuitable for the purpose is indicated at 11. Especially after passingthe first section of kneading disc 3, the mixture acquires lowviscosity, and gradually becomes a mass of more or less plastic orformable consistency. If desired, further additives can be fed into themixture by devices such as device 11 and also additional degasing portsof the type indicated at 9 may be provided. The material after passing asecond section of kneading discs 3 as seen in downstream direction isfurther degased by a degasing port 10. After passing this port theproduct has already the character of curd or grain soap. Moreover, inthis stage of the process, an excess of alkaline as may be present inthe soap is neutralized. However, it should be noted that the structureof the screw extruder as described for carrying out the processaccording to the invention eliminates reaction excesses to the extentthis is possible'within the parameter of the process.

Refining of the mass now in the form of curd or grain soap to fine orhigh quality soap occurs in the zones of the extruder downstream ofdegasing port 10. Shortly after the mass has passed this port and alsothe second section of kneading discs, metered quantities of fraganceessences and dyeing agents may be added to the mass of soap by means ofa conventional metering device 13. A feed port 12 serves to feed intothe mass quantitatively high grade waste such as accumulates when thestill soft finished soap as discharged at the discharge end of theextruder casing is pressed into the form of cakes of soap and cut ortrimmed as part of this operation.

Downstream of the addition of such high quality waste the mass of soapis further homogenized by a final section of kneading discs 3a. Afterpassing this section, the discharge screw section 20 delivers the nowfinished product to the outlet of the extruder. This outlet may includea suitably shaped die or nozzle, (not shown).

The finished refined soap is fed through a pipe 14. At the outlet end ofthis pipe a conventional shaping and cutting assembly 19 cuts and shapesthe finished but still soft soap mass as it emerges from pipe 14 intocakes of soap which then may be packaged in the usual manner.

While the invention has been described in detail with respect to acertain now preferred example and embodiment of the invention, it willbe understood by those skilled in the art, after understanding theinvention, that various changes and modifications may be made withoutdeparting from the spirit and scope of the invention, and it isintended, therefore, to cover all such changes and modifications in theappended claims.

What is claimed is:

l. A method of producing soap in continuous operation from a mixture ofstarting materials of the kind described, said method comprising thesteps of:

providing a continuous treatment line in the form of a screw extrudercomprising an elongate casing having at one end a feed port and at theother end a discharge port and including a pair of conveyor screwsrotary within the casing parallel to the axis thereof and havingdifferently pitched screw elements, said screws coacting with each otherand with the inner casing wall transverse of the lengthwise axisthereof, the wall of the casing intermediate said ports thereofincluding lengthwise spaced degasing openings, feed means for feedingthe mixture of starting materials into the casing through said feed portand further feed means disposed intermediate the ports in the casing forfeeding additives into the casing;

feeding the mixture into the casing through the feed port therein;

continuously subjecting the mixture to the action of the screw elementsas the mixture is being conveyed toward the discharge port forconverting the mixture into a pliable mass of soap;

degasing the mixture as it passes said degasing openings; and v feedingadditives into the casing and thus to the mixture as the latter passessaid further feed means.

2. A device for producing soap in continuous operation from a mixture ofstarting materials of the kind described, said device comprising:

a screw extruder including an elongate casing having at one end a feedport and at the other end a discharge port, at least one degasingopening intermediate said ports, two shafts rotary within the casingparallel to the axis thereof, screw elements secured to said shafts forrotation in unison therewith, said screw elements being divided intosections and constituting a continuous conveyor screw on each shaft, thescrew elements on at least one shaft extending along substantially thelength of the casing and including screw elements of different pitch forvarying the action of the screw elements upon the mixture as the samepasses the respective group of screw elements, the section of screwelements adjacent to the feed port constituting a feed-in section of theextruder, the screw elements in said section being in mesh and havingself-cleaning profiles; a first section interposed between thedownstream end of said feed-in section and the next adjacent downstreamsection of screw elements, the section of screw elements adjacent to thedischarge port constituting a discharge section, the screw elements insaid discharge section having a uniform pitch, and a second section ofkneading discs interposed between the upstream end of said dischargesection and the downstream end of the next adjacent section of screwelements.

3. The device according to claim-2 wherein drive means rotate the shaftsunidirectionally, and thescrew elements on the shafts are in mesh.

4. The device according to claim 2 wherein the pitch of the screwelements in certain of said sections is steeper toward said dischargeport.

5. The device according to claim 2 wherein a degasing opening in thecasing wall is disposed downstream of said first section of kneadingdiscs and communicates with the screw elements in the next adjacentdownstream section.

1. A method of producing soap in continuous operation from a mixture ofstarting materials of the kind described, said method comprising thesteps of: providing a continuous treatment line in the form of a screwextruder comprising an elongate casing having at one end a feed port andat the other end a discharge port and including a pair of conveyorscrews rotary within the casing parallel to the axis thereof and havingdifferently pitched screw elements, said screws coacting with each otherand with the inner casing wall transverse of the lengthwise axisthereof, the wall of the casing intermediate said ports thereofincluding lengthwise spaced degasing openings, feed means for feedingthe mixture of starting materials into the casing through said feed portand further feed means disposed inteRmediate the ports in the casing forfeeding additives into the casing; feeding the mixture into the casingthrough the feed port therein; continuously subjecting the mixture tothe action of the screw elements as the mixture is being conveyed towardthe discharge port for converting the mixture into a pliable mass ofsoap; degasing the mixture as it passes said degasing openings; andfeeding additives into the casing and thus to the mixture as the latterpasses said further feed means.
 2. A device for producing soap incontinuous operation from a mixture of starting materials of the kinddescribed, said device comprising: a screw extruder including anelongate casing having at one end a feed port and at the other end adischarge port, at least one degasing opening intermediate said ports,two shafts rotary within the casing parallel to the axis thereof, screwelements secured to said shafts for rotation in unison therewith, saidscrew elements being divided into sections and constituting a continuousconveyor screw on each shaft, the screw elements on at least one shaftextending along substantially the length of the casing and includingscrew elements of different pitch for varying the action of the screwelements upon the mixture as the same passes the respective group ofscrew elements, the section of screw elements adjacent to the feed portconstituting a feed-in section of the extruder, the screw elements insaid section being in mesh and having self-cleaning profiles; a firstsection interposed between the downstream end of said feed-in sectionand the next adjacent downstream section of screw elements, the sectionof screw elements adjacent to the discharge port constituting adischarge section, the screw elements in said discharge section having auniform pitch, and a second section of kneading discs interposed betweenthe upstream end of said discharge section and the downstream end of thenext adjacent section of screw elements.
 3. The device according toclaim 2 wherein drive means rotate the shafts unidirectionally, and thescrew elements on the shafts are in mesh.
 4. The device according toclaim 2 wherein the pitch of the screw elements in certain of saidsections is steeper toward said discharge port.
 5. The device accordingto claim 2 wherein a degasing opening in the casing wall is disposeddownstream of said first section of kneading discs and communicates withthe screw elements in the next adjacent downstream section.